Advertise on Bikeforums.net



User Tag List

Results 1 to 23 of 23
  1. #1
    Junior Member
    Join Date
    Aug 2008
    Location
    Monticello, Georgia
    Posts
    5
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    My rear derailer came off!!

    I've got a Nishiki backroads aluminum mountain bike. Not a very high end bike ( 10 years ago it cost me $250) but it has done me well over the years. Recently while riding a small stick caught up in the rear derailer and the next thing I knew I was walking. It seems the stick bent the bracket the derailer mounts to right across the hole at not quite a 45 degree radiused angle. The derailer was pried from the bracket. The bike is all aluminum and it appears that there was a helicoil or some type of hard metal threading in the aluminum that came out with the derailer mounting bolt. Any suggestions for repair? I have found a thread repair kit for a metric 10 x 1.0 bolt. Will the aluminum take straightening and new threads inserted or will it be too brittle? Is it worth the time and effort? The local bike shop was not very interested in attempting a repair. There are some bigger shops in town I haven't checked with yet. What do you experienced guys think?

  2. #2
    Rat Bastard mcoomer's Avatar
    Join Date
    Jul 2006
    Location
    Sammamish, WA
    My Bikes
    Cannondale Prophet, Specialized S-Works SL2, Specialized S-Works Stumpjumper
    Posts
    1,500
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    You can try straightening it and inserting a new helicoil. If that works put a new derailleur hanger on and you should be good to go. If it doesn't work, remember that Craigslist is your friend. You can find good deals on great bikes there if you don't quite have the scratch to drop on a new one from a shop.

    Mike
    It's better to burn out than fade away...or slip out of your pedal and face plant on the side of the road!!!

    '06 Cannondale Prophet
    '08 Specialized S-Works Stumpjumper
    '09 Specialized S-Works Tarmac SL2

  3. #3
    Senior Member
    Join Date
    May 2004
    Location
    Wilmington, DE
    My Bikes
    2003 Specialized Hardrock, 2004 LOOK KG386i, 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1
    Posts
    8,849
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    I would be very surprised if the derailler mounting hole was Heli-coiled. More likely, the metal that came out with the bolt was the aluminum threads, meaning that the tapped hole is now stripped. Assuming you can straighten the frame, you will need to install a thread insert (Heli-coil or similar) in order to reinstall the derailler.

    For straightening the frame, since it's aluminum it may crack when you try to bend it back. If it does, there's not much you can do to fix it that won't cost more than the frame is worth.

  4. #4
    Prefers Cicero cooker's Avatar
    Join Date
    Jul 2005
    Location
    Toronto
    My Bikes
    1984 Trek 520; 1990s Peugeot (Canadian-made) rigid mountain bike; 2007 Bike Friday NWT; misc others
    Posts
    8,430
    Mentioned
    15 Post(s)
    Tagged
    0 Thread(s)
    The derailleur hanger has to be bent back by a shop - they have a special tool for that. If the bolt hole is bent it seems unlikely to me it can be straightened and reinforced, but I'm not an expert. I think you're looking at a new bike.

  5. #5
    Senior Member BCRider's Avatar
    Join Date
    Mar 2008
    Location
    The 'Wack, BC, Canada
    My Bikes
    Norco (2), Miyata, Canondale, Soma, Redline
    Posts
    5,429
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    If it bent right at the hole so that part of the threaded section is bent one way and the other part is another way then that hanger is toast. YOu'll never bend it back in such a way that the derrailleur will fit back in. Also being aluminium it will more likely crack the end off as you try to straighten it.

    Now MOST aluminium frames used replaceable dropout hangers just for this reason. Look at your frame again to see if it has one of those. If it doesn't then it's new frame time.
    Model airplanes are cool too!.....

  6. #6
    Junior Member
    Join Date
    Aug 2008
    Location
    Monticello, Georgia
    Posts
    5
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    (Man, you guys gotta get a life!!) Should of read... Man, you guys are awesome. I never expected to have quality responses from several members so quickly! Thanks for the replies!
    I'm sure it is a one piece derailluer hanger with no dropout. Looks like that would be a good idea! There is some kind of thread material that is not aluminum that came out with the deraillure mounting bolt. I guess I'll order the repair kit and try to fix it but I agree it may be time for a new bike. Thanks for the info. The guy at the bike shop wanted to sell me a Giant Boulder SE (2008 model). $300 good?
    Last edited by mkmumf; 08-18-08 at 06:51 AM.

  7. #7
    Prefers Cicero cooker's Avatar
    Join Date
    Jul 2005
    Location
    Toronto
    My Bikes
    1984 Trek 520; 1990s Peugeot (Canadian-made) rigid mountain bike; 2007 Bike Friday NWT; misc others
    Posts
    8,430
    Mentioned
    15 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by mkmumf View Post
    I guess I'll order the repair kit and try to fix it
    Even if you miraculously rethread the hole, the derailleur won't be lined up with the cogs and you will get skipping or autoshifting. However if the repair kit is cheap I guess there's no harm in trying. Try to bend the hanger straight before you mount the derailleur. If you use the derailleur as a lever to try to bend the frame you may damage the derailleur.

  8. #8
    Senior Member BCRider's Avatar
    Join Date
    Mar 2008
    Location
    The 'Wack, BC, Canada
    My Bikes
    Norco (2), Miyata, Canondale, Soma, Redline
    Posts
    5,429
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    A trick that may help you with bending the aluminium back.... And this only works for bare aluminium so if it is painted then you're toast.

    If you heat the metal to a certain point the stress hardening from the original bending will be relieved and you can bend the hanger back possibly without the hanger snapping off.

    The trick is to blacken the metal with soot from a candle or a closely held Bic lighter flame. Make sure the metal is in the yellow part of the flame so you get the most blackening.

    Then light up a propane torch and play the flame over the blackening until the black dissappears. Cool the metal either with air, time or water and then clamp on whatever you need to bend it back. It is now softer than it was and you can bend the part back to shape.

    It works amazingly well. I've done a few motorcycle levers for off road bikes over the years and they all held up well after staightening. Normally they would snap when you try to bend them back straight.
    Model airplanes are cool too!.....

  9. #9
    Senior Member DieselDan's Avatar
    Join Date
    Mar 2003
    Location
    Beaufort, South Carolina, USA and surrounding islands.
    My Bikes
    Cannondale R500, Motobecane Messenger
    Posts
    8,524
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by mkmumf View Post
    Man, you guys gotta get a life!! Thanks for the replies!
    Offend us then thank us? WTF?
    Bikes use brakes to stop.

    If your bike has breaks, don't ride it.

  10. #10
    Senior Member DannoXYZ's Avatar
    Join Date
    Jul 2005
    Location
    Saratoga, CA
    Posts
    11,495
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    There's two distinct ideas going on here. First is that "you" probably won't be able to bend back the hanger and have it be aligned correctly.

    Second is that "it is possible" to get it fixed, but you'll need to find a qualifed shop that's familiar with the procedure. Of utmost importance is an alignment tool to verify that the hanger is straight. And yeah, they'll also have an insert kit to repair the threads. Helicoil is ghetto at best. Time-serts or EZ-lok is a much better choice.

  11. #11
    Senior Member
    Join Date
    Aug 2005
    Location
    Pittsburgh, PA
    My Bikes
    '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
    Posts
    25,405
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by mkmumf View Post
    Man, you guys gotta get a life!! Thanks for the replies!
    I'm sure it is a one piece derailluer hanger with no dropout. Looks like that would be a good idea! There is some kind of thread material that is not aluminum that came out with the deraillure mounting bolt.
    I agree that this sounds like a rather gratuitous insult to those trying to provide the info you requested. Your manners need work.

    If the threads that came out with the derailleur were steel, not aluminum, it's possible the derailleur hanger was repaired in the past with something like this:

    http://www.biketoolsetc.com/index.cg...em_id=VR-130/1

    Dealers commonly use them to repair damaged rd mounting holes or it might even be an OEM part to strengthen an inherently weak threaded hole.

  12. #12
    Rat Bastard mcoomer's Avatar
    Join Date
    Jul 2006
    Location
    Sammamish, WA
    My Bikes
    Cannondale Prophet, Specialized S-Works SL2, Specialized S-Works Stumpjumper
    Posts
    1,500
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by HillRider View Post
    I agree that this sounds like a rather gratuitous insult to those trying to provide the info you requested. Your manners need work.
    I thought gratuitious insults were what we thrived on around here, kind of like the gratuitious nudity in Fast Times at Ridgemont High that makes the movie a classic (Phoebe Cates when I was in high school )
    It's better to burn out than fade away...or slip out of your pedal and face plant on the side of the road!!!

    '06 Cannondale Prophet
    '08 Specialized S-Works Stumpjumper
    '09 Specialized S-Works Tarmac SL2

  13. #13
    Junior Member
    Join Date
    Aug 2008
    Location
    Monticello, Georgia
    Posts
    5
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Firstly may I apologize again for my earlier crude and totally out of place statement regarding you guys. I can only assure you that the intentions were never intended to be taken in a negative manor.
    Hillrider, that dropout repair kit ( http://www.biketoolsetc.com/index.cg...em_id=VR-130/1 ) looks like it would make an excellent repair. Probably stronger than the original installation. Have you had any experience with it?
    I've attached a few pics of the damage and the insert that came out for your viewing pleasure.

    Thanks
    Attached Images Attached Images

  14. #14
    Oldtimer borgagain's Avatar
    Join Date
    Mar 2008
    Location
    Foothills of the Catskills in New York
    My Bikes
    1972 Raleigh LTD, 1985 Cannondale SR300 (2), 1986 ROSS Eurotour, 1991 Giant Sedona MTB, 1992 Trek Antelope MTB
    Posts
    221
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Take a look at the before and after derailer pictures of this aluminum framed Schwinn (subject of a previous post). The hanger was bent primarily at the mounting hole. I bent it back with an adjustable wrench. There was no indication of cracking or any failure in the material. I doubt that it would survive another bending but it's working fine, for now...

    Better quality aluminum alloy might not take the abuse as well but it's certainly worth a try to straighten it. What have you got to lose?
    Resistance is futile. Mechanical enhancement is inevitable. You will be assimilated into your bicycle.
    My Bikes

  15. #15
    Senior Member
    Join Date
    Aug 2005
    Location
    Pittsburgh, PA
    My Bikes
    '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
    Posts
    25,405
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by mkmumf View Post
    Firstly may I apologize again for my earlier crude and totally out of place statement regarding you guys. I can only assure you that the intentions were never intended to be taken in a negative manor.
    Hillrider, that dropout repair kit ( http://www.biketoolsetc.com/index.cg...em_id=VR-130/1 ) looks like it would make an excellent repair. Probably stronger than the original installation. Have you had any experience with it?
    I've attached a few pics of the damage and the insert that came out for your viewing pleasure.

    Thanks
    Appology accepted. "Tone of Voice" doesn't translate very well over the internet does it?

    I have no personal experience with these inserts (fortunately) but I have heard many reports that they work very well and, as I mentioned, are a commpn LBS repair technique. The inserts come in a couple of lengths depending on the dropout/hanger thickness being worked on. If you can adequately align your current hanger, one of these should get you back in business.

  16. #16
    Senior Member
    Join Date
    May 2004
    Location
    Wilmington, DE
    My Bikes
    2003 Specialized Hardrock, 2004 LOOK KG386i, 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1
    Posts
    8,849
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by mkmumf View Post
    I've attached a few pics of the damage and the insert that came out for your viewing pleasure.
    After viewing the picture, I stand corrected. That most certainly is a thread insert, likely from a previous repair. The issue you may run into now though is that since a previous repair has been done, material has already been removed to install the thread insert. You might not have enough material left in place to install a standard thread insert again. A machine shop should be able to make you a special insert that would do the trick though.

  17. #17
    Senior Member DannoXYZ's Avatar
    Join Date
    Jul 2005
    Location
    Saratoga, CA
    Posts
    11,495
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    The bent hanger doesn't look that bad. Since the threads are already damaged, you don't have to worry about that. The shop can just bend/pound the hanger straight. Then install an insert. I recommend the 1-piece EZ-lok as it's much stronger than a Helicoil and thicker too, so the existing hole can be re-drilled and tapped. It comes with red permanent Loctite on the threads of the insert, and I recommend applying more on the fresh threads in the hanger. Finally they can align it as the final step of the repair.

  18. #18
    messenger
    Join Date
    Aug 2008
    Location
    WLA
    My Bikes
    pinarellos and a colnago
    Posts
    599
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    thread........

    dude this is a 75 dollar bike on craigslist..............dude take the bike to the shop--- have them use the proper alignment tool from park and heli it----dude............ Performance has a sale! 250.... new ride ---- safe ---- big breath!

  19. #19
    messenger
    Join Date
    Aug 2008
    Location
    WLA
    My Bikes
    pinarellos and a colnago
    Posts
    599
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    wow

    i have now looked at the pictures--- buy a new bike..... enjoy todays technology----

  20. #20
    Your mom
    Join Date
    Aug 2006
    Posts
    2,546
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I don't think that's a helicoil, I think it's the spring from your derailleur. I'd be leery of bending an all-aluminum dropout, and would probably take it to the LBS, which I never do. Barring that, I think you now have yourself a single speed mountain bike. They're all the rage.

  21. #21
    Junior Member
    Join Date
    Aug 2008
    Location
    Monticello, Georgia
    Posts
    5
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thanks for all the info. I talked to a guy at bike tools etc and ordered the insert that Hillrider suggested. Should be here Fri. I'll let you know how it turns out. This seems the best choice as I can't determine the amount of material that came out with the threads and the finished product should be plenty strong. The repair should be the easy part. After reading about aligning the dropout bracket it looks like that will be the bigggest challenge.
    I realize this isn't a high end bike and I actually found a Specialized Rockhopper for $95 but fixing this for about $8 will be a fun challenge and will get me where I need to go.
    Attached Images Attached Images

  22. #22
    Junior Member
    Join Date
    Aug 2008
    Location
    Monticello, Georgia
    Posts
    5
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Well, a few hours of work and I'm back on the road! The insert was easy to install. I reformed the bracket before making any adjustments to the deraillure and it must be close cause it is shifting solid. Thanks for the tips!

  23. #23
    Senior Member DannoXYZ's Avatar
    Join Date
    Jul 2005
    Location
    Saratoga, CA
    Posts
    11,495
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Hey good job!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •